Spark plug



Feb. 4, 1936. E. B. NIOWOSIELSKI,

S PARK PLUG Original Filed May 1, 1950 INVENTOR.

Edward B. Nowos/elskl BY whi f/f 10 plug which embodies novel means for preventing Patented Feb. 4,

UNITED STATES PATENT OFFICE 2,029,669 1 SPARK PLUG Original application May. I, 1930, Serial No.

449,039, Divided and this application'Novembe! 5, 1934, Serial No. 751,601 i 8Claims. (01.1l2 3169) This invention relates to ignition systems for internal combustion engines and more particularly to spark plugs.

, One of the objects of the present invention is to provide an improved spark plug'which is both mechanically and electrically strong, and is capable of long service without mechanical or the escape of gases from the engine cylinder through the spark plug structure with a consequent loss of compression.

A further object is to provide a spark plug embodying a novel gas-tight seal and an im-' proved shielding means which on account of its'simplicity and smallnumber of parts is rugged in structure, cheap to manufacture and easy to assemble.

Several embodiments of the present invention are illustrated in the accompanying drawing, but it is to be expressly understood that said drawing is for the purpose of illustration only and is not.

to be construed as a definition of the limits of the invention, referencebeing had for this purpose to the appended claims.

In the drawing: I

Fig, 1 is a side elevation partly in section of one embodiment of the present invention;

Fig. 2 is a side elevation partly in section of a second embodiment of the invention.

Referring now to the drawing, wherein like reference characters indicate like parts throughout the several views, Figs. 1 and 2 illustrate an improved spark plug which embodies novel means for forming a gas-tight seal to prevent the escape of gases through the body of the spark. In the form' plug from the engine cylinder. shown, said plug comprises, in general, a body portion, a positive electrode and a negative electrode. Body portion 1 is exteriorly threaded as at 8 for threaded engagement with an opening in a cylinder wall of an internal combustion engine in the usual manner. The upper part of sulating sleeve I4 adjacent head l2, said washers also resting upon head I2 and preferably being of increasing outer diameter away from said head. On top of insulating washers t5 there is seated a gland l6 externally threaded as at ll, and surrounding the intermediate portion of electrode. Ill and insulating sleeve id, but separated therefrom so as to provide a space for the insertion of packing material. Gland i6 is provided with an inclined bottom portion it, the outer surface of which conforms in slope to shoulder ID of body portion l, and with an annular groove Id formed in its inner surface for purposes later to be described.

rial is forced between insulating sleeve l t and gland it under great pressure by any suitable means so that groove IQ of gland it is completely- ,filled with said material, and insulating sleeve I4 is wedged into close engagement with electrode ll thus forming a double gas-tight seal around the electrode. A plurality of other insulating washers 2!] are provided resting on top of gland l6 and surrounding substantially the remaining upper portion of eelectrode' II and insulating sleeve 94, said washers preferably decreasing in diameter toward the top of electrode ll." Retaining head 22 is then placed around the. top of electrode it and rests upon washers 2|. Retaining head 22 is provided with a counter-sunk bore 23 into-which the top of electrode II is expanded by upsetting, or any other suitable method, thus tightly clamping together on said electrode, between retaining heads washers 2|, gland l6, sleev 2i], and washers l5- Suitable meansare.provided for attaching a cable or lead to electrode II which, in the form shown, comprise a terminal member 24 constructed with a split spring tip or terminal post 25. Terminal member 24 is placed over and in body portion I is internally threaded as at 9 and contact withelectrode H and retaining head 22,

is of larger diameter-than the lower part so as to provide an inner shoulder l0. j

The positive electrode comprises a metallic spindle ll having at its lower end an .enlarged head l2, which carries a spark gap joint l3. An

insulator l4, preferably a mica sleeve, surrounds electrode ll practically throughout its length,

resting at its lower end on head l2. A plurality of insulating washers l5, preferably of mica, surround the lower portion of electrode ll and'inand is secured thereto by a spun-over flange 26 which engages a corresponding collar 21 formed on retaining head 22.

The negative electrode of the spark plug pref-* l formed in body portion 1, when the spark plug is assembled.

In assembling the spark plug, the negative electrode 28 is placed in body portion 1, flange 30 resting on shoulder 10. The positive electrode assembly as described above, is then threaded into body portion 1, the inclined bottom portion I8 01. gland l6 tightly clamping flange 30 of electrode 28 between it and shoulder II! to form agas-tight joint at this point. If desired, flange 30 may be doubled upon itself so as to aiford an extra thickness of metal at this point, thereby insuring the gas-tight integrity of the joint, and

' rendering'it unnecessary to employ the usual gasket.

A lead or wire 3| is connected to the terminal post 25 in any suitable manner, and, as shown, is provided with a terminal ring 32 which is adapted to slip over the split terminal 25. Lead 3| is covered with suitable insulation 33, and when the plug is shielded in the manner illustrated and claimed in my co-pending application Serial No. 449,039 (of which application the present case is a division) the insulation is in turn covered by a metallic sheathing of woven wire, or other suitable material, having contact with the shield portion of the plug.

In Fig. 2 there is illustrated another embodiment of the present invention. In this form, the packing material placed between the insulating sleeve II and gland 16 comprises a pair of wedge rings ,48 and 48 of compressible material such as copper. These rings are placed between'sleeve l4 and gland It with their inclined faces in engagement with the base of ring 48 resting on the inclined bottom portion l8 of gland is.

Pressure is then applied, by any suitable means, to the top of ring 49, and the resultant expansion of the rings form a double gas-tight seal around electrode II in a similar manner as described for sleeve 20.

There is thus provided an improved spark plug structure which is rugged and strong both mechanically and electrically, and which is compactly and easily assembled from a small number of parts. Due to its simplicity, it is also cheap to manufacture. Novel means are provided in this spark plug for effectively preventing the escape of gases from the engine cylinder, through the spark plug structure, and thus decreasing the loss of compression, as well as prolonging the life of the plug.

It will be obvious that the invention is not limited to the specific forms described and illustrated in the drawing, but is capable of a variety of mechanical embodiments. Various changes, which will now appear to those skilled in the art, may be made in the form, details of construction, and arrangement of parts without departing from the spirit of the invention. Reference is therefore to be had to the appended claims for a definition of the limits of the invenseparated therefrom, an annular groove formed in the interior surface of said gland, and a sleeve of compressible material interposed between said gland and said insulated electrode and resting at its lower end on said inclined bottom portion, said sleeve being forcibly compressed within said gland so as to fill said annular groove, thus forming a gas-tight seal between said electrode and said gland.

2. In a spark plug, a body having an internally threaded bore, a thimble forming an electrode removably mounted in said body, a gland threaded into said body and having an inclined bottom portion, an annular groove formed in the inner surface of said gland, a center electrode operatively associated with the thimble electrode and extending through and separated from said gland, compressible insulation surrounding a portion of said center electrode, a plurality of mica discs interposed between a shoulder on the center electrode and the inclined bottom portion of said gland, a sleeve of compressible material interposed between said compressible insulation and said gland, and resting at its lower end on said inclined bottom portion, said sleeve being forcibly compressed within said gland so as to fill said annular groove and compress said insulation making a gas-tight seal between said center electrode and said gland, a plurality of mica washers surrounding said center electrode and insulation and resting on the upper surface of said gland, and cable connecting means secured to the upper end of the center electrode and having engagement with the upper one of the last mentioned washers.

3. In a spark. plug, the combination of a hollow body interiorly threaded at its upper end, an insulated electrode extending through said body, a gland surrounding said insulated electrode but separated therefrom, said gland being threaded into said body and provided with an annular groove formed in its inner surface, and compressible packing means interposed between said gland and said insulated electrode, said means comprising a soft metal sleeve which is forcibly compressed with said gland so .as to fill said annular groove, thus forming a gas-tight seal between said electrode and said gland.

4. In a spark plug having a body portion, an assembly adapted to be inserted in said body portion as a unit comprising a center electrode having a head on the lower end thereof, insulation surrounding the electrode above said head, a cup shaped electrode surrounding the lower end of said first named electrode and having an outwardly flared rim engaging a shoulder formed on the inner surface of said body portion,'a com pressible member surrounding said first named electrode, and means for forcing said compressible member intoengagement with the insulation around said electrode and at the same time firmly seating the outwardly flared portion of said cup-shaped electrode .on said shoulder, said last named means including a gland threadedly engaging the body portion of the plug and also engaging said compressible member.

5. In a spark plug, a hollow body having an internal shoulder therein, an insulated electrode extending through said body, a cup-shaped electrode within said body and having a flange engaging said shoulder, and means surrounding said insulated electrode and including a gland carried by said body for maintaining said flange in sealing engagement with said shoulder. 3

B@ in or sport: plug, o body portion, on

oeoter electrode therein, a, grounded electrode eerried by the body portion, and metallic moons engogirig o portion or soid grounded electrode for meiritoining both of the electrodes in opera tive position in said body portion.

7. In a, spark plug, a body portion, an insulated center electrode in said body portion, or grounded electrode, and means for retaining? sold center eleetrode in said body portion, said means hov me engagement with a portion olfsoid grounded eleetrode to Zorro o ges=tieht seal between the loody, grounded electrode and mesons.

it. In a, sperl; plug, e hollow body having an lntemel shoulder therein, an insulated electrode extending through said body, a, second electrode he ring e flange engaging said shoulder, and moons surrounding said insulated electrode end inoludlog e gland carried by said body for main taming sold flange in sealing engagement with said shoulder.

EDWARD 1B. NOWUSELSKI. 

